Replacement Window Installation Cost

Hello -

I am new to this forum and apologize if this questions has been posted already. We have 6 wood windows to replace in our home. With the help of our neighbor - who is a contractor, we have purchased American Craftsman 8500 replacement windows. We asked him to give us an estimate of how much he would charge us to to do the install: remove old window and replace, and he has given us a quote of $1700 which works out to about 283.00 per window. Is this reasonable for a replacement of a wood window with a vinyl window? It seemed pretty high to us - considering we were under the impression that they would be simple to replace.